by InexorableTash » Jul 11, 2006 @ 6:41am
If you don't use SetClipper and try to draw outside of the surface boundaries you'll get an error and nothing will be drawn. With SetClipper the parts inside the clipping region will be drawn and you won't get an error.
Having clipping regions be optional appears to be mostly historical; GapiDraw didn't initially have them. If you're doing your own clipping or precise rendering logic it can be instructive to have failures rather than silent mis-behavior of code during development.
Being able to change clipping regions is really cool, though - consider rendering within a "frame" that's smaller than the surface itself.